Expandable vertebral body replacement device, system, and methods

ABSTRACT

An expandable vertebral body replacement is presented. The device has an inner and outer housing longitudinally moveable on one-another which locks in place using a retention member. This can be locked or fortified by several described options. Also presented is a method for expanding said device embodiments and a system for an expandable vertebral body replacement.

CONTINUITY

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 61/802,360, filed on Mar. 15, 2013 and U.S.Utility application Ser. No. 14/216,513, filed on Mar. 17, 2014, thecontents of which are incorporated herein in their entirety.

FIELD OF THE INVENTION

This invention relates generally to spinal surgery, and moreparticularly to devices and methods of stabilization of the spinefollowing removal of a vertebral body, and replacing it with anexpandable construct to stabilize the adjacent bones and provide acorridor between them for fusion purposes.

BACKGROUND OF THE INVENTION

Damage to a vertebral bone, often due to a traumatic fracture or due toinvasion of the bone by tumor, at times requires removal of thevertebral body. This operation is known as a corpectomy. Followingcorpectomy, the resultant gap is generally filled in by a weight bearingsupport know as a Vertebral Body Replacement (VBR). This helps torestore and maintain the proper spacing between the adjacent bones, andoften provides an area for placing graft material to span the adjacentbones in order to allow a fusion to take place.

VBRs may be sized to fit the gap, or be expandable over a range. Theexpandable VBRs currently available have significant limitations. Theseinclude the inability to adequately pack graft material in the channelwithin them post-expansion, a lack of a satisfactory match of the topand bottom of the implant to the adjacent bone surfaces, and expansionmechanisms that are complex, or take an inordinate amount of time toactuate. A need remains for an implant and surgical technique that willovercome these shortfalls.

SUMMARY

Presented herein is an expandable VBR device for use in spinal surgeryfollowing a vertebral corpectomy in the cervical, thoracic, or lumbarspine. The VBR device comprises an inner housing and an outer housing.The inner housing and outer housing can move in relation to one anotherin the longitudinal direction to increase or reduce the height of theVBR device. The VBR device can be expanded within a range from thefirst, unexpanded position, to a second fully expanded position orsubstantially any position therebetween.

A system is also presented, the system comprising a VBR device and a VBRexpansion tool. In one exemplified aspect, the VBR expansion toolcomprises an actuation member coupled to a leveling member. In use,compression of the handles of the actuation member from the firstposition to the second position, moves the leveling members from aposition substantially adjacent one another to a separated position,moving the expandable VBR device from the unexpanded position to theexpanded position.

A method of placing an expandable VBR into a corpectomy defect, andexpanding the height of the device using a VBR expansion tool is alsopresented. The method comprises, accessing the desired motion segment,removing the desired vertebral body, positioning the expandable VBRdevice in place of the removed vertebral body, expanding the expandableVBR device, and fixing the expandable VBR device in the expandedposition. The method can also comprise fixing the lordotic angle of theupper and/or lower bone contact members. In another aspect, the methodalso comprises packing the graft cavity with bone growth promotingmaterials.

Related methods are also provided. Other apparatuses, methods, systems,features, and advantages of the expandable VBR device and the method ofits use will be or become apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional apparatuses, methods, systems,features, and advantages be included within this description, be withinthe scope of the expandable VBR device and the method of its use, and beprotected by the accompanying claims.

DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate certain aspects of the instantinvention and together with the description, serve to explain, withoutlimitation, the principles of the invention. Like reference charactersused therein indicate like parts throughout the several drawings.

FIG. 1 is a partially exploded front perspective view of one aspect of aVBR device;

FIG. 2 is a partially exploded perspective view of the VBR device ofFIG. 1;

FIG. 3 is a partially exploded side view of the VBR device of FIG. 1;

FIG. 4 is a partially exploded front view of the VBR device of FIG. 1;

FIG. 5 is a top plan view of the VBR device of FIG. 1;

FIG. 6 is a front view of another aspect of a VBR device in theunexpanded position;

FIG. 7 is a perspective view of the VBR device of FIG. 6 in an expandedposition;

FIG. 8 is a top plan view of the VBR device of FIG. 6;

FIG. 9 is a cut away front view of the VBR device of FIG. 6, showing aratchet mechanism for restraining the VBR from moving into the retractedposition from the expanded position;

FIG. 10 is a partial perspective view of an interior wall of an innersleeve of the VBR device of FIG. 6, showing the relationship of a toothpositioned on the interior wall of the outer sleeve with a recessdefined in the exterior wall of the inner sleeve;

FIG. 11 is a cutaway view of the engagement of the inner and outersleeve of the VBR device of FIG. 10;

FIG. 12 is a perspective view of the VBR device of FIG. 6, showing theVBR device positioned between two vertebrae;

FIG. 13 is a perspective view of the VBR device of FIG. 6, showing theVBR device with a VBR expansion tool;

FIG. 14 is a front view of one aspect of a VBR device showing an innerhousing and an outer housing;

FIG. 15 is a perspective view of the VBR device of FIG. 14;

FIG. 16 is a cut away front view of the VBR device of FIG. 14, showinggear engaged with a toothed inner surface of the inner housing;

FIG. 17 is a top plan view of a retention member; and

FIG. 18 is a perspective view of the retention member of FIG. 17;

FIG. 19 is a front view of one aspect of a VBR device in the unexpandedposition;

FIG. 20 is a front view of the VBR device of FIG. 19 in the expandedposition, illustrating wedge members angling the bone contact members;

FIG. 21 is a front view of the VBR device of FIG. 19 in a partiallyexpanded position, illustrating wedge members positioned to keep thebone contact members in a flat position;

FIG. 22 is a front view of the VBR device of FIG. 21 in the expandedposition;

FIG. 23 is a perspective view of one aspect of a retention member foruse with a VBR device;

FIG. 24 is a front elevational view of the retention member of FIG. 23;

FIG. 25 is a perspective view of a wedge member for use in a VBR device;

FIG. 26 is a perspective view of the VBR device of FIG. 19 in theunexpanded position, illustrating the VBR device between two vertebrae;

FIG. 27 is a front view of the VBR device of FIG. 19 in the expandedposition, illustrating the VBR device between two vertebrae;

FIG. 28 is a perspective view of the VBR device of FIG. 19 in theexpanded position, illustrating the VBR device between two vertebrae;

FIG. 29 is a perspective view of the VBR device of FIG. 19 in theexpanded position, illustrating the VBR device between two vertebraewith a retention member in place;

FIG. 30 is a perspective view of the VBR device of FIG. 19, showing theVBR device being expanded by an expansion tool;

FIG. 31 is a perspective view of an outer housing for a VBR device;

FIG. 32 is a front view of the outer housing of FIG. 31, illustrating ablade and slot for locking the angular position of the bone contactmember;

FIG. 33 as a top view of the outer housing of FIG. 31;

FIG. 34 is a cut-away front view of the outer housing of FIG. 31, cutalong line 32-32;

FIG. 35 is a front view of the outer housing of FIG. 31, illustrating aset screw to lock the blade into position;

FIG. 36 is a top plan view of the outer housing of FIG. 31;

FIG. 37 is a front cut-away view of the outer housing of FIG. 31, cutalong line 35-35 of FIG. 33;

FIG. 38 is a front cut-away view of the outer housing of FIG. 31, cutalong line 38-38 of FIG. 36;

FIG. 39 is a partially transparent perspective view of an outer housingfor a VBR device having an elongate pivot member to lock the angularposition of the bone contact member;

FIG. 40 is a front view of the outer housing of FIG. 39;

FIG. 41 is a partially transparent top plan view of the outer housing ofFIG. 39;

FIG. 42 is a cut-away side view of the outer housing of FIG. 39, cutalong line 42-42 of FIG. 40;

FIG. 43 is a front view of the outer housing of FIG. 39, illustratingthe upper bone contact member in the angled position;

FIG. 44 is a partially transparent top plan view of the outer housing ofFIG. 39, showing a trough for receipt of a pivot member;

FIG. 45 is a cut-away side view of the outer housing of FIG. 39, cutalong line 45-45 of FIG. 43;

FIG. 46 is a cut-away front view of the outer housing of FIG. 39, cutalong line 46-46 of FIG. 44;

FIG. 47 is a perspective view of the outer housing of FIG. 39,illustrating the trough and engagement portion of the trough;

FIG. 48 is a section view of a section of the outer housing of FIG. 39showing the section of FIG. 47;

FIG. 49 is a partially transparent perspective view of a VBR device,illustrating deployable spikes corresponding to an upper bone contactmember;

FIG. 50 is a partially transparent cut-away perspective view of the VBRdevice of FIG. 49, illustrating ramp members associated with deployablespikes;

FIG. 50A is a perspective view of a ramp member and deployable spikesfor use in the VBR device of FIG. 49;

FIG. 51 is a side view of the VBR device of FIG. 49, illustrating thespikes in a retracted position;

FIG. 52 is a cut-away front view of the VBR device of FIG. 49, cut alongline 52-52 of FIG. 51;

FIG. 53 is a rear view of the VBR device of FIG. 49, illustrating thespikes in a retracted position;

FIG. 54 is a cut-away side view of the VBR device of FIG. 49, cut alongline 54-54 of FIG. 53;

FIG. 55 is a side view of the VBR device of FIG. 49, illustrating thespikes in a deployed position;

FIG. 56 is a cut-away front view of the VBR device of FIG. 49, cut alongline 56-56 of FIG. 55;

FIG. 57 is a rear view of the VBR device of FIG. 49, illustrating thespikes in a deployed position;

FIG. 58 is cut-away side view of the VBR device of FIG. 49, cut alongline 58-58 of FIG. 57;

FIG. 59 is a partially transparent perspective view of a VBR deviceillustrating deployable flexible spikes;

FIG. 60 is a partially transparent side view of the VBR device of FIG.59, illustrating the spikes in a retracted position;

FIG. 61 is a cut-away top plan view of the VBR device of FIG. 59, cutalong line 61-61 of FIG. 60;

FIG. 62 is a rear view of the VBR device of FIG. 59, illustrating thespikes in a retracted position;

FIG. 63 is a cut-away side view of the VBR device of FIG. 59, cut alongline 63-63 of FIG. 62;

FIG. 64 is a partially transparent side view of the VBR device of FIG.59, illustrating the spikes in a deployed position;

FIG. 65 is a cut-away top plan view of the VBR device of FIG. 59, cutalong line 65-65 of FIG. 64;

FIG. 66 is a rear view of the VBR device of FIG. 59, illustrating thespikes in a deployed position;

FIG. 67 is a cut-away side view of the VBR device of FIG. 59, cut alongline 67-67 of FIG. 66;

FIG. 68 is a perspective view of one aspect of a VBR device and a VBRdevice expansion tool;

FIG. 69 is a side view of the VBR expansion tool of FIG. 68,illustrating the VBR expansion tool engaged with the VBR device in theretracted or unexpanded position;

FIG. 70 is a side view of the VBR expansion tool of FIG. 68,illustrating the VBR expansion tool engaged with the VBR device afterexpansion; and

FIG. 71 is a side view of a scissor member for a VBR expansion tool.

DESCRIPTION OF THE INVENTION

The present invention can be understood more readily by reference to thefollowing detailed description, examples, and claims, and their previousand following description. Before the present system, devices, and/ormethods are disclosed and described, it is to be understood that thisinvention is not limited to the specific systems, devices, and/ormethods disclosed unless otherwise specified, as such can, of course,vary. It is also to be understood that the terminology used herein isfor the purpose of describing particular aspects only and is notintended to be limiting.

The following description of the invention is provided as an enablingteaching of the invention in its best, currently known aspect. Thoseskilled in the relevant art will recognize that many changes can be madeto the aspects described, while still obtaining the beneficial resultsof the present invention. It will also be apparent that some of thedesired benefits of the present invention can be obtained by selectingsome of the features of the present invention without utilizing otherfeatures. Accordingly, those who work in the art will recognize thatmany modifications and adaptations to the present invention are possibleand can even be desirable in certain circumstances and are a part of thepresent invention. Thus, the following description is provided asillustrative of the principles of the present invention and not inlimitation thereof.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a “plate” includes aspects having two or moreplates unless the context clearly indicates otherwise.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

Terms used herein, such as “exemplary” or “exemplified,” are not meantto show preference, but rather to explain that the aspect discussedthereafter is merely one example of the aspect presented.

Additionally, as used herein, relative terms, such as “substantially”,“generally”, “approximately”, and the like, are utilized herein torepresent an inherent degree of uncertainty that may be attributed toany quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue.

In one aspect, presented herein is an expandable VBR device 10 for usein spinal surgery following a vertebral corpectomy in the cervical,thoracic, or lumbar spine. The VBR device comprises an inner housing 100and an outer housing 200. The inner housing 100 and outer housing 200can move in relation to one another in the longitudinal direction toincrease or reduce the height of the VBR device 10. In one exemplifiedaspect, the outer housing defines in interior cavity 210 within whichthe inner housing can nest in the unexpanded position. In anotheraspect, the inner housing 100 and outer housing 200, together, define agraft cavity 215 for the placement of bone graft material, to include,but not limited to, allograft, bone substitute, or other biocompatiblebone growth promoting materials.

The VBR device can be expanded within a range from the first, unexpandedposition, to a second fully expanded position or substantially anyposition therebetween. In an exemplified aspect, an interior surface 220of the outer housing 200 comprises a toothed surface 225. A toothedsurface can be positive, such as protrusions, or negative, such asrecesses. In one aspect, the exterior surface 110 of the inner housing100 comprises a toothed surface 125, as well. Each tooth can comprise acam 130, 230 surface and a flat surface 135, 235. In one aspect, thetoothed surfaces are complimentarily opposite, meaning that in theexpanding direction, the cam surface 230 of a tooth 225 on the outerhousing 200 mates with the cam surface 130 of a tooth 125 on the innerhousing 100 and, in the retracting direction, the flat surface 235 of atooth 230 on the outer housing 200 engages the flat surface 135 of atooth 125 on the inner housing 100. This relationship permits the twohousings to move in the expanding direction in a ratcheting manner, butprevents the two housings to move in the retracting direction.

In another exemplified aspect, each tooth 125, 225 can comprise two camsurfaces 130, 230, without a flat surface. Additionally, the VBR devicecan comprise a retention member 300 configured to engage at least aportion of the toothed surface of the inner housing to preventlongitudinal up and down movement of the outer housing with respect tothe inner housing. In one aspect, the retention member can be a u-shapedmember sized to horizontally slide around at least at least portions theexterior surface 110 of the inner housing 100.

In still another exemplified aspect, the inner housing may define awindow 160 having a toothed edge portion 165. In this aspect, a gear 260can be positioned on the outer housing 200 configured to engage thetoothed edge portion 165 of the window 160 of the inner housing 100. Inone aspect, the exterior surface 110 of the inner housing may comprise atoothed surface 125. The VBR device can also comprise a retention member300 configured to engage the exterior surface of the inner housing torestrict movement of the inner housing with respect to the outerhousing. The retention member can be a c-ring configured to at leastpartially wrap around the inner housing and engage at least one of theteeth on the external surface of the inner housing.

The retention member 300 can have, for example, edge portion 310 thatare cammed and complimentary to the toothed surfaces 225 of the interiorsurface 220 of the outer housing 200. However, since the toothedsurfaces are generally sloped, the edge portion of the retention memberneed not be angled, sloped, or cammed. It is also contemplated that theedge portion 310 of the retention member have a top surface 315 that issubstantially flat in order to retain the flat portion 235 of thetoothed surfaces 225 of the interior surface 220 of the outer housing200. In still another aspect, the retention member can be removablyattached to a portion of the inner housing. As illustrated in FIG. 20,the top portion 140 of the inner housing 100 can comprise a tongue 145and the edge portion 310 of the retention member 300 can comprise acorresponding groove 320 to enable the retention member to slide intoposition at a top portion of the inner housing. In this aspect, when theretention member is positioned in engagement with the inner housing, theouter housing is prevented from retracting downward toward theunexpanded position, while still being able to ratchet in the upwarddirection toward the expanded position. When the retention member ismoved out of engagement with the inner housing, the outer housing cantherefore move in either direction substantially unimpeded.

In an exemplified aspect, the VBR device comprises an upper bone contactmember 400 and a lower bone contact member 450. The upper bone contactmember 400 has an upper bone contact surface 410 configured for contactwith a lower portion of a first vertebra. The lower bone contact member450 has a lower bone contact surface 460 configured for contact with anupper portion of a second vertebra. One or both of the upper and lowerbone contact members can be substantially planar. In one aspect, theupper bone contact member can be pivotally connected to a portion of thetop portion 240 of the outer housing. The pivot point 415 can, forexample, be in substantially the center of the of the upper bone contactmember, enable the upper bone contact member to angulate in either theanterior or posterior direction. The function permits the VBR device toadapt to the anatomy of the patient. As can be appreciated, the lowerbone contact member 450 can be pivotally connected to a portion of thebottom portion 150 of the inner housing 100. The pivot point 465 can,for example, be in substantially the center of the of the lower bonecontact member 450, enabling the lower bone contact member to angulatein either the anterior or posterior direction.

In still another aspect, the VBR device comprises an inner and outersleeve 500, 550, wherein the outer and inner sleeves are configured tomove longitudinally with respect to one another from the retractedposition to the expanded position. The inner and outer sleeve define aninterior cavity 555. In an exemplified aspect, an interior surface 560of the outer sleeve 550 comprises a toothed surface 565. In one aspect,the exterior surface 510 of the inner sleeve 500 comprises a toothedsurface 515, as well. Each tooth can comprise a cam surface 516, 566 anda flat surface 517, 567. In one aspect, the toothed surfaces arecomplimentarily opposite, meaning that in the expanding direction, thecam surface of a tooth on the outer sleeve mates with the cam surface ofa tooth on the inner sleeve and, in the retracting direction, the flatsurface of a tooth on the outer sleeve engages the flat surface of atooth on the inner sleeve This relationship permits the two sleeves tomove in the expanding direction in a ratcheting manner, but prevents thetwo sleeves to move in the retracting direction. As one skilled in theart can appreciate, in lieu of complimentary toothed surfaces, the innerand outer sleeves can comprise one toothed surface and define acomplimentary recess 520 on the other surface, where the recess 520 hasa flat interior edge 522 that compliments the flat surface 567 of thetooth of the other surface.

In this aspect, the upper bone contact member can be hingedly attachedto a top portion 580 of the outer sleeve and the lower bone contactmember can be hingedly attached to a lower portion 530 of the innersleeve. This configuration permits angulation of the bone contactmembers to compliment the adjacent vertebral bodies. In an exemplifiedaspect, the inner and outer sleeves nest within one another and define apillar window 570. In this aspect, the VBR device comprise a pillar 20configured to fit within the interior cavity 555 to be placed into theinterior cavity via the pillar window 570. In an exemplified aspect, atop portion 21 of the pillar is angled and the bottom portion of thepillar 22 is also angled. The top portion 21 of the pillar engages aportion of the upper bone contact member 400 and the angle of the topportion of the pillar places the upper bone contact member to thedesired angle for lordosis. Similarly, the bottom portion 22 of thepillar engages a portion of the lower bone contact member 450 and theangle of the lower portion of pillar places the lower bone contactmember to the desired angle for lordosis. The pillar, of course,substantially prevents the VBR device from moving from the expandedposition to the retracted position.

One or both of the upper and lower bone contact members 400, 450 cancomprise spikes 600 or protrusions to facilitate engagement with therespective vertebral bone. The spikes can be integral with therespective upper or lower bone contact member or they can be deployedafter insertion into the disc space. In one exemplified aspect, asillustrated in FIG. 42, the respective bone contact member can define atleast one spike aperture 610 in communication with a spike cavity 620. Aspike can be sized to fit substantially completely therein the spikecavity 620. In one aspect, a ramp member 630 can be positioned within achannel 650 defined in the bone contact member defining an orifice 635that is partially coaxial with the spike cavity 620. The edges of theorifice and the spike comprise complimentary cam 640 and follower 645surfaces such that, when the ramp member 630 is moved in a firstdirection, the spike rides along the ramp member, raising it to extendthe distal portion of the spike above the bone contact surface of thebone contact member. Of course, it is contemplated that the spike cancomprise a plurality of spikes and the spike cavity can comprise aplurality of spike cavities. Additionally, the ramp member can comprisea plurality of ramp members. Each ramp member may define a plurality oforifices, each corresponding to a spike and spike cavity, as illustratedin FIG. 42.

In another aspect, the spikes 600 can comprise a flexible material, suchas Nitinol or spring steel. In this aspect, the spikes can be initiallyembedded within a channel 650 in the respective bone contact member in aplane that is substantially parallel to the respective bone contactsurface. Each of the spike apertures 610 can be associated with a rampedor angled portion 655 of the bone contact member such that, when theflexible spike is moved toward the spike aperture, the spike will angleupward and through the spike aperture.

In one exemplified aspect, one or both of the bone contact members canbe locked in angular position, substantially restraining the respectivebone contact member from pivoting with respect to the respective inneror outer housing. In one aspect, as shown in FIG. 25, the respectivebone contact member can comprise a blade 700 positioned on a secondsurface 420, 470 of the bone contact member 400, 450, opposite the bonecontact surface, and substantially perpendicular thereto the secondsurface. In this aspect, the top of the outer housing, or the bottom ofthe inner housing, depending on which bone contact member is beingdiscussed, can define a blade slot 710 configured for receipt of theblade 700. The respective housing can also define a threaded aperture720 configured for receipt of a set screw 730 adapted to fit within thethreaded aperture 720 and engage a portion of the blade 700 tosubstantially fix its position with respect to the respective housing.As shown in the figures, the blade can define a plurality of bladeapertures into which the end of the set screw can engage to assist inholding the respective bone contact member in angular position.

In another aspect, as shown in FIG. 32 a, the respective bone contactmember can comprise at least one elongate pivot member 800 configured tofit within a respective trough 810 defined in the top surface 240 of theouter housing (or the bottom surface of the inner housing). The elongatepivot member 800 can comprise a substantially cylindrical shape, butother shapes are contemplated. In one aspect at least a distal end 805of the elongate pivot member can define a raised and/or depressedpattern 820. In this aspect, a portion of the trough 810 defines acomplimentarily patterned raised and/or depressed section 825. In oneaspect, the pattern is a starburst, as shown in FIG. 32 a, but othercomplimentary patterns are contemplated. In this aspect, urging thedistal end of the pivot member into engagement with the patternedportion of the trough fixes the angle of the bone contact member withrespect to the respective housing. For example, a set screw 830 may beused, as shown in FIG. 37, to urge the pivot member into engagement withthe patterned portion of the trough.

In still another aspect, the respective bone contact member can belocking into angular position by insertion of a wedge member 900 in thespace between the bone contact member and the respective housing. FIG.20 shows a wedge member between the upper bone contact member and theouter housing and another wedge member between the lower bone contactmember and the inner housing. The wedge members can be configured invarious ways to achieve the desired angle. In one aspect, the wedgemember can be fixed to the VBR with a fixation device, such as a screw.

A system is presented, comprising a VBR device and a VBR expansion tool1000. In one exemplified aspect, the VBR expansion tool 1000 comprisesan actuation member 1100 coupled to a leveling member 1200. Theactuation member comprises a first handle 1110 hingedly coupled to anopposed second handle 1120. The first handle comprises a proximal end1112 configured to be held by a person's hand and a distal end 1114,with a hinge point 1130 therebetween. The second handle 1120 alsocomprises a proximal end 1122 configured to be held by a person's handand a distal end 1124, with the hinge point therebetween 1130. Theactuation member is configured to move from a first position where theproximal ends of the handles are at their most separated position andwhere the distal ends of the handles are at substantially their closestposition, to a second position where the proximal ends of the handlesare compressed toward one another and where the distal ends of thehandles are separated. The VBR expansion tool can also comprise acompression retention member 1140 hingedly connected to a proximal endof one of the first or second handles configured to engage a catchmechanism 1145 positioned on the other handle. The compression retentionmember, when engaged with the catch mechanism, substantially maintainspressure on the first and second handles.

Continuing with the VBR expansion tool, the leveling member 1200comprises an upper leveling member 1210 and a lower leveling member1220, the two leveling members are separated by and connected by ascissor member 1250. The scissor member comprises a first scissor arm1260 and a second scissor arm 1270. The scissor arms 1260, 1270 arepinned substantially in their middle section 1280, similar to commonscissors. The proximal end 1262 of the first scissor arm 1260 is pinnedto a proximal end 1212 of the upper leveling member 1210 and the distalend 1264 of the first scissor arm comprises a first pin 1266 configuredto engage, in sliding relation, an elongate slot 1218 defined in thelower leveling member. Similarly, the proximal end 1272 of the secondscissor arm 1270 is pinned to a proximal end 1222 of the lower levelingmember 1220 and the distal end 1274 of the second scissor arm comprisesa second pin 1276 configured to engage, in sliding relation, andelongate slot 1216 defined in the upper leveling member. In thisfashion, as the proximal end of the upper leveling member is separatedfrom the proximal end of the lower leveling member, the distal end ofthe upper leveling member is also raised and equally separated from thedistal end of the lower leveling member. As can be appreciated, therelation of the arms to the leveling members can be reversed withsimilar results.

As illustrated in FIG. 69, the distal end of the first handle 1114 canbe hingedly connected to the proximal end 1214 of the upper levelingmember and the distal end 1124 of the second handle can be hingedlyconnected to the proximal end 1222 of the lower leveling member.Additionally the distal end of the upper and lower leveling members cancomprise forks 1300 to engage portions of the expandable VBR device. Inuse, compression of the handles of the actuation member from the firstposition to the second position, moves the leveling members from aposition substantially adjacent one another to a separated position. Bydoing so, when the forks are engaged with portions of the inner andouter housings, the expandable VBR device moves from the unexpandedposition to the expanded position.

A method of placing an expandable VBR into a corpectomy defect, andexpanding the height of the device using a VBR expansion tool ispresented. The method comprises, accessing the desired motion segment,removing the desired vertebral body, positioning the expandable VBRdevice in place of the removed vertebral body, expanding the expandableVBR device, and fixing the expandable VBR device in the expandedposition. The method can also comprise fixing the lordotic angle of theupper and/or lower bone contact members. In another aspect, the methodalso comprises packing the graft cavity with bone growth promotingmaterials.

Although several aspects of the invention have been disclosed in theforegoing specification, it is understood by those skilled in the artthat many modifications and other aspects of the invention will come tomind to which the invention pertains, having the benefit of the teachingpresented in the foregoing description and associated drawings. It isthus understood that the invention is not limited to the specificaspects disclosed hereinabove, and that many modifications and otheraspects are intended to be included within the scope of the appendedclaims. Moreover, although specific terms are employed herein, as wellas in the claims that follow, they are used only in a generic anddescriptive sense, and not for the purposes of limiting the describedinvention.

What is claimed is:
 1. A vertebral body replacement device comprising:an outer housing defining an interior cavity and having an interiortoothed surface; an inner housing nesting within at least a portion ofthe interior cavity of the outer housing, the inner housing moveablealong a longitudinal direction to increase a height of the vertebralbody replacement device; a retention member removably engageable with aportion of the inner housing, the retention member defining at least oneouter edge that is cammed and complimentary to the interior toothedsurface of the outer housing, wherein the retention member, whenpositioned in engagement with the inner housing, permits expansion ofthe vertebral body replacement device while preventing contraction ofthe vertebral body replacement device; an upper bone contact memberhaving an upper bone contact surface; and a lower bone contact memberhaving a lower bone contact surface.
 2. The vertebral body replacementdevice of claim 1, wherein the inner housing and outer housing define agraft cavity for the placement of bone graft material.
 3. The vertebralbody replacement device of claim 1, wherein the upper bone contactmember is pivotally connected to a portion of a top portion of the outerhousing enabling the upper bone contact member to angulate in either ananterior or posterior direction.
 4. The vertebral body replacementdevice of claim 1, wherein the lower bone contact member is pivotallyconnected to a portion of a lower portion of the inner housing enablingthe lower bone contact member to angulate in either an anterior orposterior direction.
 5. The vertebral body replacement device of claim4, wherein at least one of the upper and lower bone contact memberscomprise means for locking the respective upper or lower bone contactmember into a desired angular position.
 6. The vertebral bodyreplacement device of claim 5, wherein the means for locking therespective upper or lower bone contact member into a desired angularposition comprises a wedge member configured to be removably positionedbetween the respective bone contact member and the housing to which therespective bone contact member is connected.
 7. The vertebral bodyreplacement device of claim 1, wherein at least one of the upper andlower contact surfaces define a plurality of surface protrusionsconfigured to engage adjacent bony structure.
 8. The vertebral bodyreplacement device of claim 7, wherein the plurality of surfaceprotrusions are spikes that can move from a undeployed state, wheresubstantially all of the spike is beneath the respective contactsurface, to a deployed state, where at least a portion of the spikeextends above the respective contact surface.
 9. The vertebral bodyreplacement device of claim 8, further comprising means for deployingthe spikes.
 10. A method for replacing a vertebral body comprising thesteps of: accessing a desired motion segment; removing a desiredvertebral body; positioning an expandable VBR device in place of theremoved vertebral body; expanding the expandable VBR device; and fixingthe expandable VBR device in the expanded position; and wherein the VBRdevice comprises: an outer housing defining an interior cavity andhaving an interior toothed surface; an inner housing nesting within atleast a portion of the interior cavity of the outer housing, the innerhousing moveable along a longitudinal direction to increase a height ofthe VBR device; a retention member removably engageable with a portionof the inner housing, the retention member defining at least one outeredge that is cammed and complimentary to the interior toothed surface ofthe outer housing, wherein the retention member, when positioned inengagement with the inner housing, permits expansion of the vertebralbody replacement device while preventing contraction of the vertebralbody replacement device; an upper bone contact member having an upperbone contact surface; and a lower bone contact member having a lowerbone contact surface.
 11. The method of claim 10, wherein the innerhousing and outer housing define a graft cavity for the placement ofbone graft material and the method further comprises the step of packingthe graft cavity with bone growth promoting materials.
 12. The method ofclaim 10, wherein the upper bone contact member is pivotally connectedto a portion of a top portion of the outer housing enabling the upperbone contact member to angulate in either an anterior or posteriordirection, and the lower bone contact member is pivotally connected to aportion of a lower portion of the inner housing enabling the lower bonecontact member to angulate in either an anterior or posterior direction,the method further comprising the step of fixing a lordotic angle of atleast one of the upper and lower bone contact members.
 13. A system forreplacing a vertebral body comprising: an expandable VBR devicecomprising: an outer housing defining an interior cavity and having aninterior toothed surface; an inner housing nesting within at least aportion of the interior cavity of the outer housing, the inner housingmoveable along a longitudinal direction to increase a height of theexpandable VBR device; a retention member removably engageable with aportion of the inner housing, the retention member defining at least oneouter edge that is cammed and complimentary to the interior toothedsurface of the outer housing, wherein the retention member, whenpositioned in engagement with the inner housing, permits expansion ofthe VBR device while preventing contraction of the expandable VBRdevice; an upper bone contact member having an upper bone contactsurface: and a lower bone contact member having a lower bone contactsurface; and a VBR expansion tool.
 14. The system of claim 13, whereinthe inner housing and outer housing define a graft cavity for theplacement of bone graft material.
 15. The system of claim 13, whereinthe upper bone contact member is pivotally connected to a portion of atop portion of the outer housing enabling the upper bone contact memberto angulate in either an anterior or posterior direction and the lowerbone contact member is pivotally connected to a portion of a lowerportion of the inner housing enabling the lower bone contact member toangulate in either an anterior or posterior direction.
 16. The system ofclaim 15, wherein the VBR expansion tool comprises: an actuation memberhaving a first handled and an opposed second handle, wherein the firstand second handles are hingedly coupled at a hinge point, the hingepoint being positioned between a proximal end and a distal end of eachof the first and second handles; and a leveling member coupled to theactuation member, the leveling member having an upper leveling memberand a lower leveling member, the upper and lower leveling membersseparated by and connected by a scissor member, wherein the scissormember comprises a first scissor arm and a second scissor arm pinnedsubstantially in their middle section and wherein the proximal end ofthe first scissor arm is pinned to a proximal end of the upper levelingmember and the distal end of the first scissor arm comprises a pinconfigured to engage, in sliding relation, an elongate slot defined inthe lower leveling member, and wherein the proximal end of the secondscissor arm is pinned to a proximal end of the lower leveling member andthe distal end of the second scissor arm comprises a pin configured toengage, in sliding relation, and elongate slot defined in the upperleveling member such that, as the proximal end of the upper levelingmember is separated from the proximal end of the lower leveling member,the distal end of the upper leveling member is also raised and equallyseparated from the distal end of the lower leveling member.
 17. Thesystem of claim 16, wherein the distal end of the first handle ishingedly connected to the proximal end of the upper leveling member andthe distal end of the second handle can be hingedly connected to theproximal end of the lower leveling member.
 18. The system of claim 16,wherein the distal end of the upper and lower leveling members eachcomprise forks to engage portions of the expandable VBR device, whereby,in use, compression of the handles of the actuation member from a first,separated position to the second, compressed position, moves theleveling members from a position substantially adjacent one another to aseparated position.